Noncondensing steam engine



May 8, 1928.

J'. STUMPF NONCONDENSING STEAM ENGINE Filed Nov. 10. 1920 4 Sheets-Sheet 2 I I nventor fim MMM May 8, 1928.

1,668,927 J. STUMPF NONCONDEN SING S TEAM ENGINE Filed Nov. 10. 1920 4 Sheets-Sheet 3 iwen i gr May 8, 1928';

' 1,668,927 J. STUMPF NONCONDENSING S'ITEAM ENGINE Filed NOV- 10. 1920 4 Sfwetsfiheet 4 Patented May 8 1928. e

' JOHANN srUMrF, or BERLIN. GERMANY.

.NONCONDENSING. STEAM EEINGINE.

Application filed November 10, 1920,;Seria 1 No. 423,201, and in Germany. October 14, 1920.

,The invention relates to steam .engines, and s especially applicable to nonrcondens- 111g steam engines.

The objectis to provide improved method and means for transforming pressure energy of exhausting stealnof a; plural cylinder steam engine into kinetic energy fl1'l(l- 1ltll'lZ- 'ing said kinetic energy derived. from the ex haustingsteam of one cylinder in withdrawing residual exhaust from another cylinder. The invention is especially applicable to cylindersin which steam has a uni-directional flow. r.

. The .invention comprises the method of utilizingthe entire pressure ot theexhaust of one cylinder at the point of release, that is the point at which the exhaust port hegins toopen, to draw exhaust steam from another cylinder.

This method involves anov-erlap of the exhaust periods of two or morecylindcrs in such manner that the maximumvelocity in theexhaust of one cylinder is available for acting upon the residualexhaust of another cylinder. p

v The invention also comprises improved means for effecting the method above defined, including. anejector. and'means for ilr v ntingt expans o los of velocity until after-the exhaust'has passed the ejector; nozzle formations for preventing loss in transforming initial pressure energy into kinetic energy, and diffuser formations for hanging k n t energy in p es ur en rgy in order to discharge against the atmosphere, and in combining w h the means above recited, an elongated piston for covering the main exhaust ports at all times, except near theend of the stroke. The invention also includes exhaust valves so timed that the ex haust of one cylinder will open ata proper interval before thefinalclosing ofthe exhaust of another cylinder. The .invention also covers other details and formations herein. particularly described.

Referring to the drawings which illustrate merely by way of exannole,.suitable and pre-. ferred means foreffecting my invention Fig. 1 is a diagram showing the time of opening of the exhaust ports of a twincylinder uniflow engine. p

Fig. 2 is a steam diagramo-f said engine. ,Fig. ,3 is a diagram showing the time of opening of the. exhaust portsof a-triple cylinder uniflow steamengine. 1 I .Fig. 4 comprises three indicator diagrams,

the; piston,

with cut-off at three different- .positions of .Fig. '5 is a cross-section through thecyL inders and a .smoke bok of alocomotive.

Fig.5Fis atopplan View of formation 11.

' Fi 6 is apart elevation partsection of a cylinder and valve gear therefor. Fig. 7 is a. diagrammatic section showing two-cylinder engine with the cranks at 90, with release, Fig. 7" showingthe In the, diagram, ,F 1 of a crank circle 0t.a.,t-w n cyhnder unafiow engine, is shown the time of opening the exhaust ports, controlled..-by,the ,piston, with .an advance of 25% in the leadof the exhaust, with cranks at 90. i

. h Qdiea emwand I) r p s e c cular motion of theengine when, the exe haustports of one cylinder areopen, and c and (Z represent the circular IIlOtlOIlOf the engine when the exhaust ports of the other y ind qare open I ,It will;tl1ushe seen that the opening of the e haustports of, opposite cylinders overlap tov the extontiof the shaded parts 6, f, 5/ and 11; 1" that th'eiexhaust port of one. cylinder is opened. before the exl aust port of the op? posite cylinder is closei'l,

The entire initial energy otthe exhaustat the point of releaseis utilized indrawijng residual exhaust steam from the opposite cylinder justheifore its exhaust, port closes.

The. diagram, Fig.2, shows an indicator card inhlack lines, with the-expansion curve carriedto theexhaustpressure shown by the shaded portion. The shaded portion A shows the amount of steam exhausted during ,the simultaneous opening of the exhaust ports of both cylinders and represents the energy which is ,utilized to draw .ofi the residualsteam of the opposite cylinder and drop the pressure in the opposite cylinder as indicatedf at Z, i 0 represents the increase. in the work done in the cylinder due to the lowering ofthepressujre from Zto m.

tons of a triple cylinder uniflow steam engine with an advance of ten per cent in the lead of the exhaust and with cranks at. 120. The arcs M, N, P, Q, R and S show thetime in the cycle when theexhaust valves are open. The shaded. sections show the overlapping of the exhaust valve openings. The

time of opening of the exhaust of one cylinder is always partially covering that of another, so that, at all times, residual steam is drawn out from one or two other cylinders. The diagram, Fig. 4, represents three indicator diagrams or cards. with cut-off at three different positions of the piston. A cut-oif at 4.4% gives sutlicient exhausting energy to produce an exhaust pressure of 0.68 atm., abs, corresponding to a vacuum of 32%, if ample losses by friction etc., are assumed in the calculation. A cut-off at 609 0 or will certainly entail a vacuum of 50%; This, in combination with the commencement of the compression at allows a. clearance. space of the same size as used in ordinary loctmiotives. The vacuum produced in a triple cylinder engine will always be larger than in a twin cylinder engine, as the rcsidual steam s better drawn out by the other cylinders than by the one cylinder. The short length of the usual exhaust pipe will not allow too much suction uponthe residual steam of the same cylinder.

In a triple cylinder engine the exhaust will also show the greatest uniformity, and, when used. with a locomotive, will produce a good intensive and effective combustion. There will be a substantial reduction of steam consumption and a substantial increase of the capacity of the engine. A cutoff at dili'erent positions of the piston will entail different vacua and diil'm'ent compressions as indicated in Fig. 4.

In the cross-section view, Fig. 5, the exhaust nozzles 3 and 4 are placed in the cylinder wall. The area is first smoothly reduced and then smoothly and gradually enlarged. Only two nozzles, 3 and 18, and 4 and 16 are arranged in the wall of each cylinder; one being continued by a pipe lead ing to the ejector-union 7, 8, 9, 10, 11, and the conunonsmoke stack 15. 16, 17. The other-nozzles 18 and 19'lead by other pipes 20. 21 to heating devices not shown; I

ln'the triple cylinder engine, three exhaust pipes meet at the union, the cross-section of which is almost tripled in. comparison with the cross-section of .one single cylinder exhaust pipe. 7

In Fig. 6, the cylinder is shown with single beat valves 22, 22, a Walchaert gear and an actuating cam with rollers. 'The resulting motion of the "Valchaert gear is com- 'mmicated by rod 23 to the lever 24 upon shaft 25, mounted in a casing 26, and bearing aswingingcam 27 provided with curved faces acting upon the rollers attached to swinging levers 28, 28. These levers transmit motion to horizontal slide pieces 29, 29, which push the spindles of the single beat valves 22, 22. The pistons 31 are movable in a cylinder formation 32 arranged in the central partof the casing2ti. *Steam or compressed air may be introduced'into the space between the pistons 31, by means of a pipe 80, to press them apart, thus engaging elements 29, 29 and opening the inlet valves in order to remove all resistance for the locomotive when drifting or empty running. By making the advance in the lead of the exhaust in a nniflow cylinder as large as 25%, the length of the piston may be reduced and consequently the length and weight of the cylinder. In fact the cylinder has about the same weight as an ordinary cylinder. The single beat valves are tight against high pressure, are very light and simple and need no lubrication.

The exhaust ports 3 and 4 in the cylinder *alls, which are controlled by the piston, are made in the form of steam nozzles which have the effect of transforming pressure energy of the steam into kinetic energy. The form of these nozzles, as shown in Fig. 5 at 3 and 4, as well as the form of the piston as shown in Fig. 6, are made to cooperate so as to give good nozzle efficiency during the time of partial uncovering of the ports. Both may be adapted as to shape and size so as to give those cross-sections of free area required by the decreasing difference of pressure. a By combining the exhaust pipes of two or more cylinders, in an ejector like formation, a partial vacumn is created in one cylinder by theaction of the exhaust from another cylinder or cylinders. The position of the cranks at ninety degrees in a twin cylinder engine and of one hundred and twenty degrees in a triple cylinder engine will favor this suction action, if sulficient advance on the lead of the exhaust is used; twenty-five per cent will answer all requirements in two cylinders, and ten per cent in three. This will correspond to a release'at seventy-five and ninety per cent of the stroke of the piston, generally required for locomotives with two or three cylinders respectively. By release or point of release is meant the point at which the exhaust port begins to open, thereby releasing the exhaust steam from the cylinder. It is important that the entire pressure of the exhaust at the point of re lease, be utilizedin order to produce the maximum velocity, and that the exhaust ill) shall not be permitted itoexpandheyond that incident to its passage through pipes 5.1to S to the ejector. Therefore the exhaust connections are so designed that therezshall be no pressure or velocity losses, due to unnecessary expansion, I

Thatpart of theexhaust steam flowing with the highest speed from one cylinder, will just meet with thatpart of the exhaust steam from the other cylinder flowing with the lowest speed. c, I g

The nozzle formation shown as having its most restricted partin the cylinder ,as at 3 and 4%, Fig. 5. yThis positio'n op tiona-l so long as it is located before the ejector union so that all pressure.energy will be transformed into speed encrgybeforesaid union, where the "cross-section should be enlargedto secure 1 good suction. After the ejector union, the cross-section of the combined exhaust pipe should be gradually increased up to the highest end, which shall have the largest cross-section, as shown in Fig. 5. Asa rule the smallest crosssection is in the cylinder wall, the largest at the end of the combined exhaust pipe. This is altogether different from the usualpractice in locomotives.

In the diffuser thus realized in the combined exhaust pipe, the equalized flow of exhaust steam is transformed into exhaust steam With less speed and higher pressure. Just suflicient speed is left to produce sufficient air draft in the. furnace. Exhaust steam and combustion gases are thus mixed in the formation 17, Fig. 5, forming a flow of mixture which will be partially transformed into pressure energy in the diffuser of thechimney 15.

Itis important properly toproportion the size of the smallest area of the different nozzles at the cylinders. For the average production of steam, wit-h about twenty-five per cent advance in the lead of the exhaust, they should offer such area as to secure a flow of steam during nearly the whole time of the opening of the exhaust port. In this manner the greatest uniformity in the combined flow of steam and the greatest suck-. ing action will be obtained. I

It is preferable, whenthe exhaust is used to aroduce draft in the furnace, to use two difl 'users, one 10, after having taken up the residual steam of a cylinder or cylinders, and the other 15, after having taken up the combustion gases.

The partial vacuum in the exhaust of the uniflow cylinder, will in itself increase the efliciency and capacity of the steam engine, because the required clearance space is sub stantially reduced, the compression also'is changed, so that great compression is combined with small cut-off and small compression with large cut-off, as it should be.

All exhaust pipingshould be made with .transformation of the, res eaei'eyin .-siw ene he t int .1 sure is ecu'red withfthe maximunrefliciency.

smooth i ternal surfaces, ,iyithrno corncrs or sudden changes direction ganld. a. The arrangement, should be suclrthat t e riinsinission of the same, the impact of steam from one cylinder with. the residual steam of i other cylinder and the impact of steam vrf i combustion ases,a1id'the transformation of the resulting speed energy of. the .inixture ifer e e mesp eri p expansive medium having high initial pressure and subsequent expansive force.

lVhile the invention especially adapted for locomotives, it may be used to great advantage for similar machinery, such as steam tractors, steam vehicles and common exhaust steam engines with two or more cylinders.

It is known that non-condensing uniflow steam engines ordinarily require a largeclearance space on account of the great length of compression and on account of the pressure with which the compression is started. There is consequently the disadvantage of excessive clearance space and a large steam consumption. This disadvantage can be substantially reduced either by reducing the terminal exhaust pressure or by increasing the initial pressure or by combinin both.

The advantage therefore of the present method and means oi'er the common practice, is that, instead of an over-pressure, a

partial vacuum, 1 up to one-half aim. is'

created in the exhausting cylinder. This decreases the steam consumption and yetleaves sufiicient velocity of exhaust steam, through the smoke stack to producethe required draft in the fire-box of the locomotive.

The energy for accomplishing this result is taken from that partrepresented in the diagram Fig. 2, as lost by incomplete expansion.

What I claim is 1. In a plural cylinder engine, the com bination of means comprising exhaust ports and passages having nozzle formations to prevent loss in transforming the initial pres sure energy of the exhaust to kinetic energy and means comprising an ejector for utilizing said kinetic energy derived from the exhaust of one cylinder to draw the exhaust from another cylinder.

2. Ina plural cylinder engine, the com- 7 bination of means comprising exhaust ports from the exhausting side of the cylinder,

the combination otmeans forming an ejector common. to all exhaust ports, and port controlling means so timed that the exhaust from one cylinder will operate to withdraw the exhaust steam from another cylinder.

4. In a plural cylinder engine having main exhaust ports controlled by the power piston operating so that, when exhaustii'lg, there shall be no opening of the main exhaust port or ports, except the exhaust open ing from the exhaustin side of the cylinder, the said cylinders also having supplen'ientary exhaust ports and valves controlling the same, the combination of means forming an ejector common to all exhaust ports and portcontrolling means so timed that the exhaust from one cylinder will operate to withdraw the exhaust steam From another cylinder. 1

In testimony that I claim the foregoing as my invention I have signed my name.

JOHANN STU MPF. 

